Railway-traffic-controlling apparatus



Sept. 3, l 92 9.

L. O. GRONDAHL RAILWAY TRAFFIC CONTROLLING APPARATUS Filed May 4, 1928 mm fi QR k NWQW @UNI MW W m m R L 5 fi U N N D 9 r w [6 g Q IIY W m -b M .w E

INVENTORZ 600- Ska/144151,

Patented Sept. 3, 1929.

UNITED STATES 1,727,204 PATENT OFFICE.

LABS O. GRONDAHL, 0F PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO THE UNION SWITCH & SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

RAILWAY-TRAFFIC-C'ONTROLLING APPARATUS.

Application filed May 4,

My invention relates to railway traffic controlling apparatus, and particularly to apparatus of the type wherein impulses of current are periodically supplied to the track rails, and the train is provided with governing means selectively responsive to the periodicity of such impulses.

One feature of my invention is the provision, in apparatus of this character, of means for at times periodically eliminating an impulse of the current supplied to the rails and means on the train responsive to the trackway current when an impulse is periodically eliminated but not when the impulses are continuously supplied.

I will describe one form of apparatus embodying my invention, and will then point out the novel features thereof in claims.

The accompanying drawing is a diagrammatic view showing one form of apparatus embodying my invention.

Referring to the drawing, the reference characters 1 and 1 designate the track rails of a stretch of railway track over which traffic normally moves in the direction indicated by the arrow. These rails are divided, by means of insulated joints 2, into a plurality of successive track sections, of which only one section AB is shown complete in the drawing. Train controlling current is supplied to the rails of this section from a suitable source of energy such as an alternator G,

and this current may be of a frequency of the order of the usual commercial alternating current such for example as cycles or 100 cycles per second.

The supply of current to the track rails is controlled by a coding device designated in general by the reference character X and comprising a plurality of rotatable cams each designated by the reference character C with a suitable distinguishing exponent. The cams C are driven at a constant speed by a suitable motor M which is supplied with current from the alternator G. The cam C is provided with a plurality of swells 8 spaced about its periphery and which swells successively engage a contact 3 to periodically close the contact as the cam C is rotated. In similar manner the cams C and C are provided with different numbers of swells 8 which control contacts i and 5, respectively. One terminal of the alternator G is constantly connected with rail 1 of section Al3, and the 1928. Serial No. 275,092.

other terminal of the alternator is connected 1 with the rail 1 through one of the contacts 3, l, or 5, of the coding device X, and through an auxiliary coding device Y which is hereinafter explained.

It is manifest that the alternating current supplied to the track rails by alternator G is periodically varied at the frequency of operation of the contact of the device X that is interposed between the alternator and the track rail 1'. The coding device X may be constructed to cause such variations at any reasonable frequencies, but for purposes of illustration, I will assume that the cams C are rotating at 20 revolutions per minute, that cam C has 4; swells, that cam C has 6 swells, and that cam C has 9 swells. The selection between the several contacts of the coding device X in accordance with traffic conditions may be accomplished in any suitable manner such, for example, as by means of a home relay H and, a distant relay L. The circuits for controlling these two relays form no part of my present invention and are omitted from the drawing for the sake of simplicity. When relays H and L are both energized, so that front contact 66 of relay H and front contact '77 of relay L are closed, current from alternator Gr,

which current I will assume to be of 100 cycles per second, is supplied to the track rails through contact 5 operated by cam C Under these conditions the alternating current supplied to the trackway is periodically varied at a frequency of 180 cycles per minute. Current supplied to the trackway under these conditions, I will hereinafter term the proceed code. When relay H is energized and relay L is de-energized, the closing of back contact 7-7 of relay L places contact l. controlled by cam C in the trackway circuit, and under these conditions the trackwa is supplied with 100 cycle current interrupted at a frequency of 120 cycles per minute; this current I shall hereinafter term the caution code. In similar manner when relay H is de-energized, the closing of back contact 6--6 of this relay completes a circuit from alternator G to the track rails through contact 8 operated by cam C Under these conditions the trackway is supplied with 100 cycle current interrupted at a frequency of 80 cycles per minute, which current I will call the slow code. The three codes thus far referred to will hereinafter be designated as the primary codes.

A train, which is indicated diagrammatically at V, is provided with governing means which is responsive to the frequency of the periodic variations in the cycle current supplied to the trackway. In the present embodiment of my invention the train is pro vided with two magnetizable cores 11 and 11 located in advance of the forward axle 10 and disposed in inductive relation to the two track rails 1 and 1, respectively. Core 11 is provided with a winding 12, and core 11 is provided with a winding 12, the two windings 12 and 12 being connected in series in such manner that the voltages induced therein by train controlling current flowing in opposite directions in the track rails at any instant are additive. VVindings 12 and 12 are connected through an amplifier 13 and a. transformer Q, with a polarized relay R. When train controlling current is being supplied to the trackway, pulsating energy is delivered to the primary of transfo 'mer Q at the frequency of the periodic variations in such trackway current. F or each impulse of energy supplied to transformer Q, during the increase of such current an impulse of one relative polarity is supplied to relay It, and during the decrease of such current an impulse of the opposite relative polarity is supplied to the relay. The relay It is responsive to the relative polarity of the current supplied thereto, and it follows that when the train controlling current supplied to the rails is being periodically varied, the relay R is operated to close its normal and reverse contacts 15-15 and 1515 alter nately at a frequency which corresponds to the frequency of the variations of the truckway current.

Associated with relay It is a transformer T comprising a primary 16 and a secondary 17. Direct current is supplied to the primary 16 of transformer 'I from a suitable source of energy such as a battery I), and the supply of such current is periodically varied in accordance with the frequency at which relay It operates. As shown in the drawing, when relay It energized in one direction to close contact 1515, current flows from battery D through the lower half of primary 16 in one direction, but when contact 15-15 is closed current flows from battery D, through the upper half of primary 16 in the opposite direction. It follows that when relay R is operated intermittently, the current in primary 16 of transformer I is periodically reversed and reestablished in original direction at the same frequency as the periodic variations in the trackway current.

As a result of this periodic current in the primary of transformer T, there is induced in the secondary 17 an alternating electromotive force of a corresponding frequency, which electromotive force is applied to a plurality of circuits each designated by the reference character F with a distinguishing exponent, and each comprising a reactor 18 and a condenser 19 by means of which the several circuits are tuned respectively to the frequencies of the variations in the train con trolling current. For example, circuit F is tuned to resonance at the frequency of the interruptions in the proceed code or 180 cycles per minute. A relay K is connected across a portion of the reactor 18 in circuit F through arectifier J In similar manner circuit F is tuned to resonance at 120 eycles per minute and a relay K is connected across a portion of the reactor 18 in this circuit through a rectifier J Relay K is connected, through rectifier J with a portion of the reactor 18 in circuit F which circuit is resonant at 80 cycles per minute. Each relay I: is preferably slow releasing in character.

In explaining'the operation of the apparatus thus far described, I will first assume that the proceed code is being supplied to the trackway so that the trackway current is being interrupted at a frequency of 180 cycles per minute. Relay R therefore operates at a rate of 180 cycles per minute, and alternating current of a corresponding frequency is supplied to each of the circuits F. Circuit F is resonant at this frequency, but circuits F and F are detuned, so that relay K is energized but relays K and K are de-energized. Under these conditions, current from battery D flows through front contact 24l2 l' of relay K to light a lamp 20 which displays a proceed indication.

I will now assume that the caution code is being supplied to the trackway, so that relay It is operating at a frequency of 120 cycles per second. Alternating current of this frequency is therefore supplied to the circuits F by secondary 17 of transformer T. Under these conditions the current supplied to relays K and K is not sufficient to energize them, but relay K is energized. Current then flows from battery D over back contact 2 l2l of relay K and front contact 2525 of relay K to lamp 21, thereby lighting this lamp to indicate caution.

In similar manner, when the slow code is being supplied to the trackway, relays K and K are both de-energized, but relay K is energized, and current from battery D flows through baclr contact 2424l of relay I11 back contact 25--25 of relay I 2 and front contact 26-26f of relay K to lamp 22. Lamp 22 is therefore lighted to indicate slow.

If section A-B were occupied by a second train located between train V and point B, train controlling current would be shunted away from train V by the wheels and axles of such second train. As a result relay B would be continuously de-energized. It, for this reason, or for any other reason, relay B should fail to operate intermittently, the supply of energy to all the relays K would be discontinued and these relays would be open. Current would then flow from battery D, through back contact 24--24 of relay K back contact 2525 of relay K and back contact 26-26 of relay K to lamp 28, thereby lighting this lamp to display a stop indication.

As stated hereinbefore, the train governing current suppliedto the track rails by the generator G passes through an auxiliary coding device Y. This device comprises two auxiliary cams C and C co-operating with con tacts 77 and 78 respectively in such manner that each contact is opened each time it is engaged by a swell 8 of its associated cam. The cams G and G are revolved by a ratchet wheel'81, and the ratchet wheel is in turn revolved by a pawl 80 carried by an armature 79 which is pivotally mounted at point 79 and is operated by a magnet 82. This magnet is supplied with current from generator G- through whichever one of the contacts 3, 4, or 5 is connected in the train controlling track rail circuit, and so it follows that the magnet is energized once for each impulse of train controlling current applied to the track rails. A rectifier 83 may be interposed between the rail circuit and magnet 82 so that this magnet may be of a direct current type. Contacts 77 and 78 are connected in series between contacts 8, 4, 5, .and track rail 1*, but contact 77 is shunted by a back contact 75 of a relay H when this relay is de-energized, and contact 7 8 is shunted by a back contact 76 of a relay L when the latter relay is de-energized. Relays H and L may be controlled either manually or automatically through the medium of circuits which are not shown in the drawing because they are not essential to a disclosure of my invention. T he parts are so arranged that when contact 76 of relay L is open, contact 78 eliminates every fourth impulse from the primary code which is being supplied to the track rails, whether this code be due to contact 3, 4, or 5; whereas when contact 75 of relay H is open, contact 77 eliminates every third impulse from the primary code which is being supplied to the track rails, regardless of the periodicity of the primary code. It follows that when contact 76 is open, an auX- iliary code is supplied to the track rails, which code consists of spaced recurrent groups of impulses, each group having three impulses; whereas when contact 75 is open, an axiliary code is supplied to the track rails, which code consists of spaced recurrent groups of two impulses each.

I have found that the periodic elimination of an impulse from any one of the primary codes by contact 77 or 78 does not permit the release of train carried relay K responding to such code because of the slow releasing characteristics, of these relays, and so such periodic elimination isnot reflected in the operation of lamps 20, 21, and 22, or in the op eration of any other apparatus controlled by relays K.

The train 3V is provided with apparatus which is selectively responsive to the auxiliary codes but isnot responsive to the primary codes. This apparatus involves a selector P controlled by a contact 72 of relay R. The selector P comprises a contact device 61 in the form of a disk of insulating material, pivotally supported at its center 73 and provided at its periphery with two sets of teeth 74 and 64. A spring 62 constantly urges the disk 61 in a counter-clockwise direction and the disk is therefore biased to the position in which it is illustrated, further motion in a counterclockwise direction being prevented by a stop 63 which is engaged by one of the teeth 64. Rotation of the disk 61 is controlled by an armature 57 pivoted at point 58. This armature is operated by a magnet 54 and is provided with a driving pawl 59 adapted to engage teeth 74. Disk61 is further controlled by an armature 66 pivoted at point 67 and operated by a magnet 55. This armature is provided with a resilient arm 68 carrying a latching pawl adapted to engage teeth 64. Magnets 54 and 55 are controlled by contact 7 2 of relay B, so that they are both energized each time an impulse is transmitted to the trackway by device X. When magnet 54 is deenergized the armature 57 moves, under the influence of gravity, to the position shown in the drawing, in which position the pawl 59 is swung out of the path of the teeth 74. When magnet 54 becomes energized, the armature 57 is moved in a clockwise direction and the pawl 59 engages one ofthe teeth 74 and moves the disk 61 in clockwise direction, against the bias exerted by spring 62, by an amount equal to the pitch of one tooth 7 4.

When magnet 55 is de-energized, armature 6.6 occupies the illustrated position. W hen magnet 55 becomes energized, this armature is swung in a counter clockwise direction so that the pawl 65 engages one of the teeth 64 on disk 61, and if the disk hasbeen moved away from its initial position by pawl 59 this engagement will prevent the disk from returning to such position. A bridging contact 85.8687 of the usual form is operated by armature 66 and is arranged to be closed when the armature occupies an intermediate position, but to be open when the armature occupies either extreme position. The magnet 55 is so proportioned and constructed that a time interval elapses after the magnet is deenergized and before the armature 66 is released, which interval is longer than the time interval between successive impulses in the stop code due to contact 3 of coding device X, but less than the time interval between successive groups of impulses in an auxiliary code when such auxiliary code is superposed on the proceed code due to contact 5.

The disk 17 carries at its edge two contact members 32 and 33 electrically insulated from each other and adapted to co-operate with a fixed contact finger 34. The parts are so proportioned and disposed that as disk 61 is rotated in a clockwise direction contact 34-32, or 3433 is closed according asthe disk is rotated by a code combination of two or three impulses.

Three slow releasing relays 56, 69 and are controlled by the contacts on disk 61. These relays each have a time element greater than the longest time interval between groups of impulses in any auxiliary code.

Indicating devices, here illustrated as signal lamps N and S, are cont-rolled by the relays 69 and 70.

The circuit for relay 70 is from terminal W of a suitable source of current, through wire 28, winding of relay 70, wire 39, contact 32-34 of device P, wire 35, contact 85-86- 87 operated by armature 66, wire 36, winding of relay 56, and wire 37 to terminal Z of the same source. When this circuit is closed relays 7 0 and 56 are energized. Current then flows from terminal WV, through wires 41 and 47, front contact 48 of relay 70, wire 49, lamp S, wires 45 and 45, front contact 46 of relay 56 to terminal Z, thus lighting lamp S.

The circuit for relay 69 is from terminal WV, through wires 28 and 38, winding of relay 69, wire 40, contact 33-34 of device P, wire 35, contact 858687 operated by armature 66, wire 36, winding of relay 56, and wire 37 to terminal Z. WVhen this circuit is closed, relays 69 and 56 both become energized and current flows from terminal W through wire 41, front contact 50 of relay 69, wire 51, lamp N, wires 45 and 45, and front contact 46 of relay 56, to terminal Z, thus lighting lamp N. It will be observed that the circuit for each of the relays 69 and 70 also includes relay 56, and that consequently, when either of relays 69 or 70 is energized, relay 56 will also be energized.

The operation of the selector P and the associated apparatus, is as follows: As long as any one of the primary codes is being supplied to the track rails by the coding device X, the disk 61 is stepped around in clockwise direction as far as it will go, that is, to such point that pawl 59 engages the left-hand one of the teeth 74. Both contacts 32 and 33 are then out of engagement with contact finger 34, so that both relays 69 and 70 are de-energized. I will now assume that relay L becomes energized, so that every fourth impulse is eliminated from the primary code which is being supplied to the track. During the first gap caused by the opening of contact 78 of the coding device Y, the disk 61 is released so that it turns in counter-clockwise direction .mamoa to its initial position inengagement with stop 63. During the first group of impulses in the secondary code, disk 61 is stepped around to such position that contact 33-34 closes, and when magnet 55 releases during the ensuing gap between groups of impulses, relay 69 will become energized and so will cause lamp N to be lighted. During the next group of three impulses, disk 61 will he stepped around to again close contact 33'34, so that during the ensuing gap relay 69 will again be energized. Contact 50 of relay 69 will therefore remain closed, and lamp N will remain lighted, as long as the secondary code due to earn C is being supplied to the track rails.

When relay L 'is de-energized and relay H energized, the track rails will be supplied with another secondary code consisting of recurring groups of two impulses each; this code will cause relay 70 to become energized, and this will result in lamp Sbeing lighted. The operation of the selector P due to this secondary code, will be understood without further explanation.

The secondary codes are not necessarily made up of regularly recurring eliminations of impulses in the primary code. The eliminations can be made at irregular intervals, and can be arranged in any desired group. The groups may be repeated, and the traincarried selector maybe arranged to hold the indication as long as the groups are being re peated, or a group of code impulses may be applied only once and may be used to set up an indication which may be followed by other indications, the different indications being employed to spell out words or to produce any other desired effect on the train.

Although I have herein shown and described only one form of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. Railway traffic controlling apparatus comprising means for supplying the track with train controlling current in the form of a primary code made up of regularly recurring impulses, train carried governing means responsive to said primary code, means for at times periodically eliminating one impulse to form an auxiliary code made up of a recurrent series of impulses, and train carried apparatus responsive to said auxiliary code but not to said primary code.

2. Railway traffic controlling apparatus comprising means for supplying the track with a primary code in the form of regularly recurring current impulses, means for at times periodically eliminating one impulse to form an auxiliary code made up of recurring groups of impulses, train carried apparatus responsive to said primary code but not to said auxiliary code, and other train carried apparatus responsive to said auxiliary code but not to said primary code.

3. Railway traffic controlling apparatus comprising means for supplying the track with aplurality of primary codes in the form of regularly recurring current impulses differently spaced for the difierent codes, train carried means selectively responsive to said primary codes, means for at times periodically eliminating an impulse from whatever primary code is being supplied to the track to form a secondary code consisting of recurring groups of equal numbers of impulses, and other train carried means responsive to said secondary code but not to said primary code.

4. Railway traiiic controlling apparatus comprising means for supplying the track with a plurality of primary codes in the form of regularly recurring current impulses differently spaced for the different codes, train carried means selectively responsive to said primary codes, means for at times repeatedly eliminating an impulse at different recurrent intervals from any primary code to form a plurality of secondary codes each consisting of recurring groups of equal numbers of impulses but the number of impulses in each group being dilierent for the different sec ondary codes, and other train carried means selectively responsive to said secondary codes but not responsive to said primary codes.

5. Railway trafiic controlling apparatus comprising means for supplying the track with a plurality of primary codes in the form of regularly recurring current impulses differently spaced for the different codes, train carried means selectively responsive to said primary codes, means for at times repeatedly eliminating an impulse at difierent recurrent intervals from any primary code to form a plurality of secondary codes each consisting of recurring groups of equal numbers of impulses but the number of impulses in each group being different for the diflerent secondary codes, and train carried means including a device selectively responsive to the number of impulses in each group.

6. Railway traffic controlling apparatus comprising means for supplying the track with a plurality of primary codes in the form of regularly recurring current impulses differently spaced for the different codes, train carried means selectively responsive to said primary codes, a motor device operated in synchronism with the code which is being supplied to the track, means controlled by said motor device for repeatedly eliminating an impulse from the primary code which is being supplied to the track to form a secondary code consisting of recurring groups of impulses, and train carried means responsive to said secondary code but not to said primary codes.

7 Railway traific controlling apparatus comprising means for supplying the track with a plurality of primary codes in the form of regularly recurring current impulses differently spaced for the dififerent codes, train carried means selectively responsive to said primary codes, a motor device operated in synchronism with the code which is being supplied to the track, a cam driven by said motor device, a contact periodically opened by said cam for periodically eliminating an impulse from the primary code to form a secondary code consisting of recurring groups of impulses, and train carried means responsive to said secondary code but not to said primary codes.

8. Railway trattic controlling apparatus comprising means for supplying the track with a plurality of primary codes in the form of regularly recurring current impulses differently spaced for the difierent codes, train carried means selectively responsive to said primary codes, a magnet energized by each impulse of each primary code, an armature for said magnet, a cam, a pawl and ratchet device connecting said armature with said cam whereby the cam is rotated at a rate proportional to the periodicity of the impulses of the code which is being supplied to the track, a contact operated by said cam for periodically eliminating an impulse from the primary codeto form a secondary code consisting of recurring groups of impulses, and train carried means responsive to said secondary code but not to said primary codes.

In testimony whereof I affix my signature.

LARS O. GRONDAI-IL. 

